U.S. patent application number 13/191450 was filed with the patent office on 2012-12-27 for overvoltage protection circuit.
This patent application is currently assigned to HON HAI PRECISION INDUSTRY CO., LTD.. Invention is credited to XUE-BING DENG, XIN-PING LI, XIAO-ZHAN PENG.
Application Number | 20120327544 13/191450 |
Document ID | / |
Family ID | 47361626 |
Filed Date | 2012-12-27 |
![](/patent/app/20120327544/US20120327544A1-20121227-D00000.png)
![](/patent/app/20120327544/US20120327544A1-20121227-D00001.png)
![](/patent/app/20120327544/US20120327544A1-20121227-D00002.png)
United States Patent
Application |
20120327544 |
Kind Code |
A1 |
PENG; XIAO-ZHAN ; et
al. |
December 27, 2012 |
OVERVOLTAGE PROTECTION CIRCUIT
Abstract
An overvoltage protection circuit includes a connection jack, a
path connection module, a voltage response module, and a control
module. The connection jack is connected to a power supply. The
path connection module is connected between the connection jack and
a load. The voltage response module is to output a first signal in
response to an overvoltage, and output a second signal in response
to a constant voltage. The control module is to output a
corresponding potential according to the first signal to turn off
the path connection module, and output a corresponding potential
according to the second signal to turn on the path connection
module. When the path connection module is turned off, the
connection between the connection jack and the load is disabled,
when the path connection module is turned on, the connection
between the connection jack and the load is enabled.
Inventors: |
PENG; XIAO-ZHAN; (Shenzhen
City, CN) ; DENG; XUE-BING; (Shenzhen City, CN)
; LI; XIN-PING; (Shenzhen City, CN) |
Assignee: |
HON HAI PRECISION INDUSTRY CO.,
LTD.
Tu-Cheng
TW
HONG FU JIN PRECISION INDUSTRY (ShenZhen) CO., LTD.
Shenzhen City
CN
|
Family ID: |
47361626 |
Appl. No.: |
13/191450 |
Filed: |
July 27, 2011 |
Current U.S.
Class: |
361/91.5 ;
361/91.1 |
Current CPC
Class: |
H02H 3/066 20130101;
H02H 3/20 20130101 |
Class at
Publication: |
361/91.5 ;
361/91.1 |
International
Class: |
H02H 3/20 20060101
H02H003/20 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2011 |
CN |
201110173810.3 |
Claims
1. An overvoltage protection circuit, comprising: a connection jack
for connecting to a power supply to receive power from the power
supply; a path connection module connected between the connection
jack and a load; a voltage response module to output a first signal
when overvoltage occurs, and output a second signal when
overvoltage disappears; and a control module to output a
corresponding potential according to the first signal to turn off
the path connection module, and output a corresponding potential
according to the second signal to turn on the path connection
module; wherein when the path connection module is turned off, the
connection between the connection jack and the load is disabled,
and when the path connection module is turned on, the connection
between the connection jack and the load is enabled.
2. The overvoltage protection circuit as described in claim 1,
wherein the voltage response module comprises a pnp bipolar
junction transistor (BJT), a capacitor and a resistor, an emitter
of the pnp BJT is connected to the capacitor and the anode of the
power supply, a collector of the pnp BJT is connected to the
control module, and the capacitor and the resistor are connected in
parallel between a base of the pnp BJT and the emitter of the pnp
BJT.
3. The overvoltage protection circuit as described in claim 2,
wherein a terminal of the capacitor connected to the emitter of the
pnp BJT is charged by the power supply when overvoltage occurs, the
emitter voltage of the pnp BJT is higher than the base voltage of
the pnp BJT, resulting the pnp BJT to be turned on, the voltage
response module outputs a first signal.
4. The overvoltage protection circuit as described in claim 2,
wherein a terminal of the capacitor connected to the base of the
pnp BJT is charged by the power supply when the voltage of the
terminal of the capacitor is charged to the voltage of the power
supply until the voltage difference between the emitter of the pnp
BJT and the base of the pnp BJT is less than the cut-in voltage of
the pnp BJT, causing the pnp BJT to be turned off, the voltage
response module outputs a second signal.
5. The overvoltage protection circuit as described in claim 1,
wherein the control module comprises an npn BJT, a diode, and a
resistor, the base of the npn BJT is connected to the voltage
response module, the emitter of the npn BJT is grounded, and the
collector is connected to the cathode of the diode, the anode of
the diode is connected to the path connection module and connected
to the anode of the power supply through the resistor.
6. The overvoltage protection circuit as described in claim 5,
wherein when the voltage response module outputs a first signal,
the base voltage of the npn BJT is higher than the emitter voltage
of the npn BJT, resulting the npn BJT to be turned on, the cathode
of the diode is grounded through the npn BJT to obtain a low
voltage, the anode of the diode is connected to the anode of the
power supply through the resistor, resulting in the diode turning
on, the control module outputs a low voltage to the path connection
module.
7. The overvoltage protection circuit as described in claim 5,
wherein when the voltage response module outputs a second signal,
the base voltage of the npn BJT is lower than the emitter voltage
of the npn BJT, causing the npn BJT to be turned off, the anode of
the diode is connected to the anode of the power supply through the
resistor, the control module outputs a high voltage to the path
connection module.
8. The overvoltage protection circuit as described in claim 1,
wherein the path connection module comprises a npn BJT, a n-channel
metal-oxide-semiconductor filed-effect transistor (NMOSFET), and a
resistor, the base of the npn BJT is connected to the control
module, the emitter of the npn BJT is grounded, and the collector
of the npn BJT is connected to the gate of the NMOSFET, the gate of
the NMOSFET is connected to the anode of the power supply through
the resistor, the source of the NMOSFET is connected to the anode
of the power supply, the drain of the NMOSFET is connected to the
load.
9. The overvoltage protection circuit as described in claim 8,
wherein when the control module outputs a low voltage to the path
connection module, the base voltage of the npn BJT is lower than
the emitter voltage of the npn BJT, causing the npn BJT to be
turned off, the gate of the NMOSFET is connected to the anode of
the power supply to obtain a high voltage through the resistor,
causing the NMOSFET to be turned off.
10. The overvoltage protection circuit as described in claim 8,
wherein when the control module outputs a high voltage to the path
connection module, the base voltage of the npn BJT is higher than
the emitter voltage of the npn BJT, resulting in the npn BJT
turning on, the gate of the NMOSFET is grounded to obtain a low
voltage through the conductive npn BJT, resulting in the NMOSFET
turning on.
11. The overvoltage protection circuit as described in claim 1,
wherein the voltage response module comprises a low voltage
activated switch, a capacitor and a resistor; the low voltage
activated switch comprises a first terminal connected to the
capacitor and the anode of the power supply, a second terminal
connected to the control module, and a third terminal, and the
capacitor and the resistor are connected in parallel between the
first and the third terminals.
12. The overvoltage protection circuit as described in claim 11,
wherein the low voltage activated switch is a pnp bipolar junction
transistor (BJT), the first, second and third terminals are an
emitter, a collector, and a base of the pnp BJT, respectively.
13. The overvoltage protection circuit as described in claim 1,
wherein the control module comprises a high voltage activated
switch, a diode, and a resistor, the high voltage activated switch
comprises a first terminal connected to the voltage response
module, a second terminal connected to the grounded, and a third
terminal connected to the cathode of the diode, the anode of the
diode is connected to the path connection module and connected to
the anode of the power supply through the resistor.
14. The overvoltage protection circuit as described in claim 13,
wherein the high voltage activated switch is a npn bipolar junction
transistor (BJT), the first, second and third terminals are a base,
an emitter, and a collector of the pnp BJT, respectively.
15. The overvoltage protection circuit as described in claim 1,
wherein the path connection module comprises a first high voltage
activated switch, a second high voltage activated switch, and a
resistor, the first high voltage activated switch comprises a first
terminal connected to the control module, a second terminal
connected to ground, and a third terminal connected to the second
high voltage activated switch, the second high voltage activated
switch comprises a first terminal connected to the third terminal
of the first high voltage activated switch and the anode of the
power supply through the resistor, a second terminal connected to
the anode of the power supply, and a third terminal connected to
the load.
16. The overvoltage protection circuit as described in claim 15,
wherein the first high voltage activated switch is a npn bipolar
junction transistor (BJT), the first, second and third terminals
are a base, an emitter, and a collector of the pnp BJT,
respectively, the second high voltage activated switch is a
n-channel metal-oxide-semiconductor filed-effect transistor
(NMOSFET), the first, second and third terminals are a gate, a
source, and a drain of the NMOSFET, respectively.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] The present disclosure relates to circuits and,
particularly, to an overvoltage protection circuit.
[0003] 2. Description of Related Art
[0004] When powering on an electronic device, the voltage of a
circuit of the electronic device may be raised above its load, that
is, overvoltage may occur. The overvoltage may damage some
electronic elements of the circuit. Therefore, an overvoltage
protection circuit is needed to solve the above problems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The components of the drawings are not necessarily drawn to
scale, the emphasis instead being placed upon clearly illustrating
the principles of the present disclosure. Moreover, in the
drawings, like reference numerals designate corresponding parts
throughout several views.
[0006] FIG. 1 is a block diagram of an overvoltage protection
circuit in accordance with an exemplary embodiment.
[0007] FIG. 2 is a circuit diagram of FIG. 1.
DETAILED DESCRIPTION
[0008] Embodiments of the present disclosure are now described in
detail, with reference to the accompanying drawings.
[0009] Referring to FIG. 1, a block diagram of an overvoltage
protection circuit 1 in accordance with an exemplary embodiment is
shown. The circuit 1 includes a connection jack 10, a voltage
response module 20, a control module 30, a path connection module
40, and a load 50. The connection jack 10 is connected to a power
supply 60 to receive power from the power supply 60. The path
connection module 40 is connected between the connection jack 10
and the load 50, and is configured for controlling a connection
between the connection jack 10 and the load 50. When the path
connection module 40 is on, the connection between the connection
jack 10 and the load 50 is enabled; when the path connection module
40 is off, the connection between the connection jack 10 and the
load 50 is disabled.
[0010] The voltage response module 20 outputs a first signal when
the overvoltage occurs. The control module 30 turns off the path
connection module 40 in response to the first signal, thus the
connection between the connection jack 10 and the load 50 is
disabled, and the connection between the power supply 60 and the
load 50 is also disabled. That is, when overvoltage occurs, the
load 50 cannot receive power from the power supply 60, and the load
50 is protected. The voltage response module 20 further outputs a
second signal when the overvoltage condition abates. The control
module 30 turns on the path connection module 40 in response to the
second signal, thus the connection between the connection jack 10
and the load 50 is turned on, and the connection between the power
supply 60 and the load 50 is also turned on. That is, when the
voltage from the power supply is steady, the load 50 can receive
power from the power supply.
[0011] Referring to FIG. 2, a circuit diagram of the overvoltage
protection circuit 1 is shown. The connection jack 10 includes an
anode input port 101 and a cathode input port 102 respectively
connected to an anode and a cathode of the power supply 60. The
voltage response module 20 includes a low voltage activated switch
201, a capacitor 202, and a resistor R1. In the embodiment, a pnp
bipolar junction transistor (BJT) Q1 is taken as an example to
illustrate the low voltage activated switch 201. An emitter of the
pnp BJT Q1 is connected to the anode input port 101, and a
collector of the pnp BJT Q1 is connected to the control module 30.
The capacitor 202 and the resistor R1 are connected in parallel
between a base of the pnp BJT Q1 and the emitter of the pnp BJT Q1.
A node A is formed among the emitter of the pnp BJT Q1, the
capacitor 202, and the resistor R1, and a node B is formed among
the collector of the pnp BJT Q1, the capacitor 202, and the
resistor R1.
[0012] The control module 30 includes a high voltage activated
switch 301, a diode 302, and a resistor R2. In the embodiment, an
npn BJT Q2 is taken as an example to illustrate the high voltage
activated switch 301. A base of the npn BJT Q2 is connected to the
collector of the pnp BJT Q1, an emitter of the npn BJT Q2 is
grounded, and a collector of the npn BJT Q2 is connected to the
cathode of the diode 302. The anode of the diode 302 is connected
to the path connection module 40, and connected to the anode input
port 101 through the resistor R2.
[0013] The path connection module 40 includes a first high voltage
activated switch 401, a second high voltage activated switch 402,
and a resistor R3. In the embodiment, an npn BJT Q3 is taken as an
example to illustrate the first high voltage activated switch 401,
and an n-channel metal-oxide-semiconductor field-effect transistor
(NMOSFET) Q4 is taken as an example to illustrate the second high
voltage activated switch 402. A base of the npn BJT Q3 is connected
to the anode of the diode 302, and connected to the anode input
port 101 through the resistor R2, an emitter of the npn BJT Q3 is
grounded, and a collector of the npn BJT Q3 is connected to a gate
of the NMOSFET Q4. A source of the NMOSFET Q4 is connected to the
anode input port 101, the gate of the NMOSFET Q4 is connected to
the anode input port 101 through the resistor R3, and a drain of
the NMOSFET Q4 is connected to the load 50.
[0014] When overvoltage occurs, the power supply 60 starts to
charge the capacitor 202, causing the voltage of the terminal of
the capacitor 202 connected to the emitter of the pnp BJT Q1 to be
higher than that of the terminal of the capacitor 202 connected to
the base of the pnp BJT Q1, namely, the voltage of the node A is
higher than that of the node B. Thus the base voltage of the pnp
BJT Q1 is lower than the emitter voltage of the pnp BJT Q1, and the
pnp BJT Q1 is correspondingly turned on. The power supply 60
outputs a high voltage signal such as +5V to the base of the npn
BJT Q2 through the pnp BJT Q1, namely, the voltage response module
20 outputs the first signal to the control module 30 to turn on the
npn BJT Q2. The cathode of the diode 302 obtains a low voltage
signal such as 0V, and the anode of the diode 302 obtains a high
voltage from the power supply 60, resulting in the diode 302
turning on. The base of the npn BJT Q3 is grounded through the
turned on diode 302, namely, the control module 30 outputs a low
voltage to the path connection module 40, causing the npn BJT Q3 to
be turned off. The gate of the NMOSFET Q4 obtains a high voltage
from the power supply 10, thus the NMOSFET Q4 is turned off. Thus
the voltage of the load 50 is zero, which prevents the load 50 from
being damaged by overvoltage.
[0015] When the overvoltage condition abates and when the voltage
of the node A of the capacitor 202 is charged to a predetermined
threshold value, the power supply 60 starts to charge the node B of
the capacitor 202 through the resistor R1, and the voltage of the
node B of the capacitor 202 rises gradually until the voltage
difference between the node B and node A is less than the cut-in
voltage of the pnp BJT Q1, causing the pnp BJT Q1 to be turned off.
The base of the npn BJT Q2 is connected to ground to obtain a low
voltage, namely, the voltage response module 20 outputs a second
signal to the control module 30, causing the npn BJT Q2 to be
turned off. The anode of the diode 302 is connected to the anode
input port 101 through the resistor R2 to obtain a high voltage
from the power supply 10, thus the control module 30 outputs a high
voltage to the path connection module 40, resulting in the npn BJT
Q3 turning on. The gate of the NMOSFET Q4 is grounded through the
conductive npn BJT Q3 to obtain a low voltage, resulting in the
NMOSFET Q4 turning on. Thus, the power supply 60 is connected to
the load 50, and supplies power to the load 50.
[0016] With such configuration, when overvoltage occurs, the
control module 30 turns off the path connection module 40 to cut
off the connection between the connection jack 10 and the load 50.
Thus the load 50 cannot receive power from the power supply 60 and
the load 50 is protected.
[0017] Although the present disclosure has been specifically
described on the basis of the exemplary embodiment thereof, the
disclosure is not to be construed as being limited thereto. Various
changes or modifications may be made to the embodiment without
departing from the scope and spirit of the disclosure.
* * * * *